We can get to this WWS world by simply building a lot of new systems for the production, transmission, and use of energy. One scenario that Stanford engineering professor Mark Jacobson and I developed, projecting to 2030, includes:
3.8 million wind turbines, 5 megawatts each, supplying 50 percent of the projected total global power demand
49 000 concentrated solar thermal power plants, 300 MW each, supplying 20 percent
40 000 solar photovoltaic (PV) power plants supplying 14 percent
1.7 billion rooftop PV systems, 3 kilowatts each, supplying 6 percent
5350 geothermal energy plants, 100 MW each, supplying 4 percent
900 hydroelectric power plants, 1300 MW each, of which 70 percent are already in place, supplying 4 percent
720 000 ocean-wave devices, 0.75 MW each, supplying 1 percent
490 000 tidal turbines, 1 MW each, supplying 1 percent.
We also need to greatly expand the transmission infrastructure in order to create the large supergrids that will span many regions and often several countries and even continents. And we need to expand production of battery-electric and hydrogen fuel cell vehicles, ships that run on hydrogen fuel cell and battery combinations, liquefied hydrogen aircraft, air- and ground-source heat pumps, electric resistance heating, and hydrogen for high-temperature processes.
To make a WWS world work, we also need to reduce demand. Reducing demand by improving the efficiency of devices that use power, or substituting low-energy activities and technologies for high-energy ones—for example, telecommuting instead of driving—directly reduces the pressure to produce energy.
Because a massive deployment of WWS technologies requires an upgraded and expanded transmission grid and the smart integration of the grid with battery electric vehicles and hydrogen fuel cell vehicles—using both types of these vehicles for distributed electricity storage—governments need to carefully fund, plan, and manage a long-term, large-scale restructuring of the electricity transmission and distribution system. In much of the world, we’ll need international cooperation in planning and building supergrids that span across multiple countries, because many individual countries just aren’t big enough to permit enough geographic dispersion of generators to mitigate local variability in wind and solar intensity. The Desertec project proposes a supergrid to link Europe and North Africa, and 10 northern European countries are beginning to plan a North Sea supergrid for offshore wind power. Africa, Asia and Southeast Asia, Australia/Tasmania, China, the Middle East, North America, South America, and Russia will need supergrids as well.
Although this is an enormous undertaking, it does not need to be done overnight, and there are plenty of examples in recent history of successful large-scale infrastructure, industrial, and engineering projects.
During World War II, the United States transformed motor vehicle production facilities to produce over 300 000 aircraft, and the rest of the world was able to produce over 500 000 aircraft. In 1956, the United States began work on the Interstate Highway System, which now extends for about 47 000 miles (around 75 000 kilometers) and is considered one of the largest public works project in history. The iconic Apollo program, widely considered one of the greatest engineering and technological accomplishments ever, put a man on the moon in less than 10 years. Although these projects obviously differ in important economic, political, and technical ways from the project we discuss, they do suggest that the large scale of a complete transformation of the energy system is not in itself an insurmountable barrier.
Efficient and Reliable: A 100-percent wind power, water, and solar power system can deliver all of the world’s energy needs efficiently. Jacobson and I estimated the potential supply and compared those estimates with projections of energy demand made by the U.S. Energy Information Administration. We calculated that the amount of wind power and solar power available in locations that can likely be developed around the world, excluding Antarctica, exceeds the projected world demand for power in 2030 for all purposes by more than an order of magnitude. On top of that, Jacobson and I estimate that converting to a WWS energy infrastructure can actually reduce world power demand by more than 30 percent (based on projected energy consumption in the year 2030), primarily because electric motors have less energy loss than do combustion devices.
But, the naysayers will retort, what about reliability? Can these resources deliver power reliably? Indeed they can. While it is true that no single wind-power farm or solar-photovoltaic installation can reliably match total power demand in a region, it is also true—and often not recognized—that no individual coal or nuclear plant can either.
Indeed, any electricity system must be able to respond to changes in demand over seconds, minutes, hours, seasons, and years, and must be able to accommodate unanticipated changes in the availability of generation due to outages, for example. Today’s mainly fossil-fuel electricity system responds with backup systems, power plants brought online only during periods of peak demand, and spinning reserves—that is, the extra generating capacity available by increasing the power output from already operating generators.
A WWS electricity system handles changes in demand far differently. To start with, WWS technologies generally suffer less downtime than do current electric power technologies. However, they face inherently more variability; the maximum solar or wind power available at a single location varies over minutes, hours, and days, and this variation generally does not match the demand pattern over the same timescales.
Dealing with this short-term variability can be challenging, but it is doable. Including hydropower—which is relatively easy to turn on and off as needed—in the generating package helps, as does managing demand (for example, by shifting flexible loads to times when more generating capacity is available) and forecasting weather more precisely; these have little or no additional cost. A WWS system also needs to interconnect resources over wide regions, creating a supergrid that can span continents. And it will probably need to have decentralized energy storage in residences, using batteries in electric vehicles. Finally, WWS generation capacity should significantly exceed the maximum amount of demand in order to minimize the times when available WWS power runs short. Most of the time, this excess generation capacity could be used to provide power to produce hydrogen for end uses not well served by direct electric power, such as some kinds of marine, rail, off-road, and heavy-duty truck transport.
Mark Delucchi, spectrum.ieee.org/